Passenger entry and exit doors for such vehicles are commonly approached from within the vehicle by one or more steps so as to provide reasonably easy access between street level and an interior floor level of the vehicle. The presence of such steps restricts the depth of the space available for accommodating the operation of doors within the door opening, and often precludes the use of door leaves of the glider type, which are guided for movement between a closed position across the door opening to an open position at the side of and perpendicular to the door opening. If the available depth of the bottom step is less than that required to accommodate the door leaf, a slot must be formed in the next step to receive a portion of the door leaf when open. This slot is unacceptable to many operators because of the danger of, for example, a child's foot being trapped as the door moves to its open position, and has led to continued use in many applications of bifold door structures rather than glider type doors which are more robust and have a better appearance.